A Story of Heronstairs
by jonathanburnsdowntheworld
Summary: What if... Jem and Tessa's child fell in love with Jace and Clary's child? Owen Carstairs and Aurea Herondale investigate the mystery of a boy with abilities no one has ever seen. On their journey, their attraction slowly turns into love. This is their story.
1. What's Past is Prologue

**Chapter 1**

A girl stood in the training room, flinging blades with deadly precision. The blades hit the target time and again with a resounding thud. Clary Fairchild stood at the doorway, watching silently as her heart swelled with pride. _A fine shadowhunter she would become._

As though felt like she was being watched, she whirled around with the grace of a ballerina. Then again, that was one of the many trades she'd inherited from her father. Her hair was the colour of rich gold, cascading around her face in silky waves. Emerald green eyes rested upon Clary's small frame.

"Mom, I'll be down for dinner in a minute. I swear," she smiled coyly, her eyes speaking an entirely different promise. Clary groaned inwardly.

"Why do I doubt that?" Clary sighed and continued, "That's not really why I came up here, Aurea. The Carstairs will be coming from the Los Angeles Institute next week. You remember Owen Carstairs, don't you? Be nice."

Aurea Herondale feigned an expression of mock horror, clutching her chest, "How could you say that, Mother? I'm always nice! Alas, my own mother doubts the goodness of my heart. I am deeply wounded."

Clary rolled her eyes at her daughter. _Herondales,_ she thought. A warm chest pressed against her back, strong arms circling around her waist. Clary leaned her head back and glanced up, already knowing who it was. Jace Herondale.

It had been nineteen years since they'd gotten married. Jace had grown slightly taller and more muscular, though his humour remained unchanged. He still looked like the golden lion boy that Clary met twenty one years ago, perhaps a little older. Age had been kind to him, like tender hands molding an exquisite sculpture.

"Dinner time," Jace Herondale announced, "Tonight, we feast on _hedgehogs_. Come now, the hedgehogs await our arrival." Clary smacked his arm but smiled.

In a week, they would finally meet up with the Carstairs whom they had not seen in years. Theresa Gray would certainly not have aged. Clary wondered how James Carstairs and his seventeen year old son might have changed.

She had last seen the young Carstairs at a Christmas dinner ten years ago. The boy had dark hair, somewhere between kobicha and black. His eyes, however, were a beautiful storm gray. Owen had been a quiet boy who'd seemed to develop an early love for reading. Even at the age of seven, he had been engrossed in his book, only putting it down when his mother nudged him to say hello. Clary was fond of the boy.

Seeing that Clary was lost in thought, Jace picked her up and slung her over his shoulder, marching down with her shouting in protest. Once again, Aurea was alone in the training room.

_Owen Carstairs?_ She thought. A scrawny boy with dark hair and pretty eyes came to mind. He'd held her hand once when everyone had congregated around the Christmas tree on Boxing Day. She vaguely remembered him giving her one of his books, wrapped clumsily in metallic blue paper. Aurea shrugged but looked forward to seeing him in a week.

* * *

Owen Carstairs sat on his bed, his hair rumpled from going through them with his fingers. It was a week till the trip to the New York Institute. Thinking of Aurea Herondale, with golden waves framing her face and her striking green eyes, made his heart clench. His heart did somersaults, thumping irregularly and loudly.

"Owen Carstairs," called a steady voice from the door. He raised his head and found his mother leaning by the door. Tessa Gray had not changed since he could remember.

"You did remember to pick a gift for Aurea, right? Clarissa Herondale told me she likes knives..."

Of course he'd remembered. He remembered the first time he'd seen her at Christmas, he couldn't stop staring at her. When she went to the training room to throw knives, he'd followed her there secretly. It was there that he realised her liking of knives.

Owen nodded his head and Tessa smiled knowingly. He had boxed the sleek blade and added a purple ribbon as a final touch.

"Give the present when you see her," Tessa called out, before turning her back and walking back down the corridor.

Turning back to his copy of A Tale Of Two Cities, Owen sighed. For all he knew, she probably didn't have any recollection of him... That would be _really_ awkward when he gives her the carefully wrapped present.

Beside him, Church meowed, curling into a ball on his pillow. Owen was one of the few people Church actually liked. The feline had a habit of scratching anyone who came too close for comfort. Apparently, due to some _ancient_ reason, Church had seen the world longer than any cat should have. Perhaps this was why the cat always seemed bored.

The soothing melody of a violin drifted down the hallway. James Carstairs was playing again. As a child, Owen loved to watch his father's elegant fingers move from string to string, creating beautiful music. He hoped that one day he'd be just as good as his father.

* * *

Thaddia Shadowhunter watched her mother and father lock hands. Isabelle and Simon had been married for seventeen years. When Simon Ascended, he had chosen the name, Shadowhunter. Apparently, somewhere along the family line, an ancestor had also chosen the name Shadowhunter after Ascension. At sixteen years, Thaddia was tall, hazel-eyed and also Aurea Herondale's _parabatai_.

Both Shadowhunters and Herondales reside in the New York Institute, with Isabelle Shadowhunter as the Head of the Institute. Thaddia and Aurea had known each other for as long as they could remember.

"Ted!" Somebody hissed from behind. It was Aurea.

"Hedgehogs for dinner, what do you say?" Thaddia blanched.

"Of course not, who on earth gave you that idea? Those poor things served on a platter? Count me out."

Aurea chuckled, "My father did. And shouldn't you be worrying about me instead? I'll emerge from the dining room with spikes poking out of my mouth."

"Let me present you with a simple step-by-step method. First, pluck the spikes out. Second, cook it. Third, eat." Thaddia rolled her eyes.

"Ah, a wise solution. But what fun is there in consuming a hedgehog without its spikes?" Aurea grinned and skipped out of the room.

Thaddia laughed softly, before following her out of the room.


	2. Journeys End In Lovers Meetings, Not

**Chapter 2**

Aurea Herondale stood with her arms crossed, frowning at the cat sprawled on the cushion. Just moments ago, the cat had sauntered into the doorway of the New York Institute and planted itself onto her favourite cushion while _smirking_. _Could cats even smirk?_ She exhaled in irritation.

The cat had an odd way of seeming so sure of itself, like no one else mattered. It had hissed at her when she tried to retrieve her cushion from under its furry butt. That annoyed her greatly. She glared at the cat. It studiously ignored her.

"If you were a demon, I would have cut you in half!" She huffed.

A soft, musical laughter sounded from behind. James Carstairs had entered the room. The man was slender but tall, his dark eyes smiling at her. Following him, a girl who looked no older than eighteen entered. She, too, was tall, her serious storm grey eyes taking in the interior of the room. And this, Aurea deduced, was the warlock who had angel blood. Theresa Gray.

"Don't mind Church, he's always like that," Jem mused, glancing affectionately at his cat. Aurea frowned before speaking, "Oh, I wouldn't have minded. It's just that your cat seems to have taken a liking to my cushion and I'm afraid we've become rivals for its affection."

Tessa laughed, looking bemused. _There's some of Will in her after all. _She had been anticipating her meeting with her teenage descendant, wondering how she'd grow up to be like. It was certainly obvious that she had inherited Jace's humour. The Herondales, however, no longer had Will's black hair and blue eyes.

"As you probably have guessed, I'm Aurea Herondale," Aurea announced suddenly, with a tinge of an embarrassed smile.

"Yes, it's wonderful to meet you again," Jem replied. He walked towards the cat and picked him up. Church purred. Aurea stared wide eyed. The demon of a cat _purred_. Jem carried Church away from the cushion and sat him on the ground.

"All done. Your cushion won't receive anymore declarations of love from Church." Jem smiled kindly at her.

"Come on in, Owen. It's no fun standing out there all by yourself," called Jace as he walked into the room.

There was a stark difference between Jem and Jace. While Jem was gentle and lean, Jace was strong and all muscle. The one thing they shared in common was perhaps the way they gazed protectively at their wives.

Owen Carstairs followed Jace in, his eyes roaming around till they landed on her. They widened by a fraction and he smiled warmly at her. She was like what he had imagined, slender and really pretty. Her high cheekbones and sharp nose made her look like a model. Many would have associated her with runways and fashion shows. Instead, she wielded blades and other weapons. He found that she was studying him too.

Resembling both his parents, Owen had a tinge of Asian features and his mother's serious eyes. Running a slender hand through his dark hair, Owen shifted his weight. Aurea realised that he was getting uncomfortable by her stares. She looked away.

"Hello Aurea, I'm Owen Carstairs," He spoke, smiling slightly. Aurea smiled back.

"Nice to meet you again, Owen. I suppose I could become Tour Guide Aurea for the day. Ted and I could show you around New York, if you'd like. What do you say?" Aurea suggested.

At that moment, Ted stuck her head and called out cheerily, "I think I heard my name... Or was that a hedgehog who'd said it? Hello, Mr and Mrs Carstairs. I'm Thaddia Shadowhunter." Aurea groaned. Ever since the hedgehog joke a week before, she had officially been nicknamed hedgehog. It seemed like Ted was never going to let it slide.

Confused, Owen lifted his eyebrows in question. Aurea shrugged.

"We'd love to take you around New York, Owen," Ted grinned genuinely. Seeing as both girls didn't mind, Owen nodded his head. It would probably be fun touring the city with the girls.

* * *

"Why does she call you hedgehog?" Owen whispered when Ted was walking in front of them.

"You don't want to know. I'd have to kill you if you found out." Aurea answered seriously, her bangs flooping over her eye. Irritated, she blew it away. Owen kept his hand securely behind his back, resisting the urge to brush her hair away from her face.

"Hedgehog, can we shorten your name? It's a mouthful. I'm suggesting.. Hog? Or Hedgie?" Ted called out.

Owen couldn't help but laugh. Aurea scowled.

"Are you hell bent on making me sound like a guinea pig?"

"It's either Hog or Hedgie. Take your pick, Herondale," Ted called out. Aurea could tell that she was grinning.

"Remind me why she's my parabatai... Do you have a parabatai, Owen?" Aurea probed.

Owen shook his head. Perhaps in the future. He'd heard of parabatai who fought till the end together but also parabatai who had betrayed one another. Owen wanted to be certain of his choice when the time came.

The trio stepped out of the Institute. New York was a bustling city, just like Los Angeles. Owen let the girls lead him forward.

* * *

On the other side, a black haired boy wandered around. He was very confused, remembering nothing about his life. There was a dull throbbing on his wrist. Pulling up the long sleeve, it revealed a nasty bite mark, belonging to no vampire, werewolf or demon. Whatever it was, it had torn deep into his flesh. The boy trudged on, each step he took becoming harder than the last.

As he moved forward, he spotted a girl with tresses of golden hair. The wound on his wrist began to burn with pain. There were three of them in total. _Bite them. Bite them and you'll no longer feel the pain. Bite them now._ A deep voice spoke in his head. Blinded by pain, he lunged for the golden one.


	3. Hell is Empty & All The Devils Are Here

**Chapter 3**

"Aurea, look out! _Jeremiah,_" Owen cried out as he rushed forward, naming the seraph blade in hand. Aurea ducked just in time, narrowly avoiding claws. _Claws? Was this a werewolf? Or perhaps a warlock whose giveaway were claws?_

Aurea danced away, distancing herself from the attacker. Ted moved like a snake, fluidly defending herself and lashing her whip in attack. On the other side, Owen slashed at the boy. It seemed, however, that the weapons had no effect on him. The dark haired boy was healing at an incredible rate, faster than anything she'd seen. Faster than a vampire.

She couldn't determine what Downworlder he was, if he were even one. Werewolves didn't have claws like his, impossibly sharp and strangely golden. Neither were werewolves seemingly immune to blades and whips. The boy didn't have the porcelain beauty or speed that vampires had. He wasn't using magic to defend himself either, considering that there were no bright sparks emerging from his fingertips. Aurea exhaled in frustration. Instead of joining her companions in the fight, she chose to analyse his movements. Fighting obviously wasn't doing any good, judging on the little damage Owen and Ted had inflicted.

Studying him closer, Aurea realised that he was not a trained fighter. His stance was all wrong. Legs that should have been positioned wide apart were clumsy and ineffective in closing the distance between him and his opponents. He was reliant on his left hand. Aurea realised that there was a strange bite mark on his other wrist. It probably hurt him a lot, since he didn't fight with both hands. Attacking with both hands would have given him an advantage. The boy didn't seem to be calculating any of his moves. It was as if he were rabid, blindly plunging into any possible course of action.

However, the strange boy was winning as Owen and Ted began to tire. Dark lines swirled under his skin and he smiled manically. Despite his crazed appearance, the boy still looked somewhat human. _Human_. _Boy_. Aurea whirled into the battle. Like an agile cat, she avoided his claws and grabbed his right wrist. He hissed in pain. She took advantage of this distraction and kicked him hard in the nuts. He collapsed, writhing in pain.

Owen stared at her. Ted whistled.

"Nice one, Hedgehog. Should have thought of that sooner though," Ted huffed, exhausted from the battle.

"We should probably bring him back to the Institute. I've never seen anything like him. So human, yet so different," Owen suggested, already retrieving some rope to bind him. The boy may be fast healing, but he certainly lacked in strength. He trashed about but couldn't escape. Aurea gazed at him as he bared his teeth to her. She ripped her sleeve and shoved the cloth into his mouth. Whatever he was, she didn't want him biting anyone of them.

It was fortunate that the area was deserted. Mundanes would only complicate the situation further. They brought the strange boy back to the Institute.

* * *

He was bound and the cloth in his mouth was, well, annoying. His head had begun to clear as the three strange people carried him. The pain in his wrist had receded to a dull throb once again. One of the three was a guy, tall and dark haired. The other had pretty hazel eyes and long black hair that reached the middle of her back. The last was the golden girl he'd first caught sight off.

As if she knew someone was watching her, the golden girl glanced down and frowned. He blushed, embarrassed. Very kindly, as if she felt bad for shoving the cloth in his mouth, she removed it. There was this question once again: Where were they taking him? In his clouded state, he had heard someone mention the Institute. _What on earth was an institute? The metal institution?_ He struggled a little. Despite not remembering anything, he was certain of his mental state. He knew he wasn't crazy.

"Where are you taking me? I know you think I am, but I'm not crazy," He croaked.

* * *

"And he speaks! Good heavens, the angel performs miracles," Ted spoke. She was annoyed by the fact that their one day city tour began with fighting and ended almost immediately after.

"We don't exactly think you're crazy. It's just that... we need to give you an examination," Owen tried to explain. _The silent brother kind of examination, _he added.

Aurea knew that the boy was lucid again. That was the reason why she removed the gag. She could tell from the way his eyes took in his surroundings. Aurea wanted to know if he remembered anything from his crazed state. Also, she had noted that the wound on his wrist wasn't flaming red anymore.

"Are you... okay? Do you remember anything?" Aurea questioned.

The boy grimaced. "Yeah, well, you kicked me in the nuts. But I suppose that's even, since I tried to bite you first."

Owen's eyes bulged. Aurea nodded and wondered. Ted shoved the gag back in his mouth.

"Sorry, but I don't want to risk you biting us," Ted shrugged. The boy grunted in response.

They rounded the corner and pushed open the Institute's iron gates. Two dark haired men walking in the Institute turned at the noise. One of them had slit pupils, like a cat's. He looked no older than nineteen, elaborately dressed in glittering clothes. It hardly seemed appropriate in the Institute but this was the way Magnus Bane was. Beside him, Ted's uncle, Alexander Lightwood stood tall and upright. Magnus Bane lifted a questioning eyebrow and pointed at the tied up bundle of limbs.

"My, what do we have here? Is it mundane kidnapping time?" He smiled. Alec elbowed him, "Don't give them any ideas... Anyway. Hello, Thaddia and Aurea. And you must be Owen Carstairs."

Aurea replied and gave a quick summary of the situation, "Hello Mr Bane and Mr Lightwood. This boy attacked us and it seems he heals at an astonishing speed. There's a bite mark on his wrist but it doesn't seem to belong to werewolf or vampire. He seems to go out of control only when the wound flames red."

Alec stared while Magnus nodded. "Interesting. Hello to you too, Mr Tied-Up. Well, I suppose you'd better let the others know." He gestured towards the Institute. The boy struggled a little more, as the trio carried him past Alec and Magnus.

Magnus caught a glimpse of black swirls under the boy's skin. Oddly familiar swirls. _Where had he seen them before?_


	4. By That Sin Fell The Angels

**Chapter 4**

"Well, Dad. It seems like we have a bit of a situation here," Aurea started. Jace raised his eyebrows at the sight of the boy bound in rope.

"That's an understatement. That's a mundane tied up in-" Jace paused, "Was he bitten?"

Ted nodded grimly and explained the whole situation once more. Jace nodded his head, not alarmed. After the incident with the heavenly fire, nothing really surprised Jace anymore.

"But the question is, Mr Herondale, bitten by who..." Ted continued.

"Or by what," A voice called out from the doorway. It was Magnus Bane and all his glitter. Magnus had headed back to the Institute almost immediately after he recalled why the black swirls looked familiar. They didn't just look familiar. They _felt_ familiar.

The boy sat in the middle of the room. Everyone talked as if he weren't there. It was beginning to annoy him. The boy had begun to recall somethings, his name included. There had also been a strange voice in his head. It whispered _Cassiel. That's your name._ He made a loud but muffled sound. Aurea reached out carefully and removed the cloth.

"I have a name, you know." He said, irritably.

"Well then, pray tell. Go ahead and enlighten us!" Magnus replied, his cat like eyes narrowing at the boy. It was hard to trust the boy, since his rabid state might relapse at any moment.

The boy shifted uncomfortably under Magnus' gaze and muttered, "Cassiel."

"Magnus, do you know what's wrong with the b-, I mean Cassiel?" Jace probed further. Magnus shrugged and removed his glittery coat.

"I have a theory, but why not let the Silent Brothers examine him?"

Jace nodded. Aurea glanced at Owen. He had been awfully quiet the whole time. Owen stood rigidly by Cassiel's side, almost like a statue.

Cassiel grunted, "Uh, I'm a little starved right now..." And paused when he saw the look on everyone's face. "I mean, I'm hungry for a burger. You guys have food right?"

* * *

Owen went to the kitchen to grab some food from the refrigerator. Aurea accompanied him since he didn't know where the kitchen was yet. After all, his tour had been interrupted by the unexpected incident of Cassiel.

"Are you feeling okay? You've been really quiet."

"Sorry, I was thinking about the meaning behind Cassiel's name. Do you know what it means?" Owen replied. Aurea shrugged. She hadn't exactly paid attention in lessons that involved memory work.

"It's the name of an Archangel. Cassiel means unity of God. It's been bothering me that Cassiel seems all too calm about everything. A mundane who has the urge to bite someone develops gold claws! If I were a mundane, that would have scared the hell out of me."

It did strike Aurea as odd, but he was probably still in a state of shock. Aurea didn't know or understand how mundanes reacted to things. Still, it would be wise to be cautious around Cassiel until the Silent Brothers determined what was wrong with him.

Owen decided to change the topic as he opened the refrigerator, "Christmas time is going to be unusually crowded here eh?"

That took the frown off Aurea's face. She smiled and replied, "Yeah, I guess so. I suppose I'll add your present to the pile that I have to get. Name it, what do you want?"

Owen's heart did a somersault. He could give her his present without feeling awkward after all. "I'm a simple man, just wrap it nicely."

Aurea shook her head in disapproval and tsked, "More like superficial." He laughed.

"Fine by me, I'll probably get you a severed finger or something. What colour wrapping do you favor? I need to beautify it." Owen laughed even harder.

It was easy to talk to Aurea, despite their almost nonexistent conversation history. Her easy smiles and humour drew him towards her.

"Blue," Owen replied, "I like blue."

* * *

Everyone had gathered. Jem and Tessa stood by the fireplace. The visit to the New York Institute was becoming less and less festive. Christmas would be forgotten, given the current circumstances.

Cassiel ate hungrily, wolfing down the sandwiches like he had been starved. He wasn't exactly clear whether he had in fact been starved, given that he didn't remember much. The voice in his head had stopped talking to him.

_May I examine you? I will need to go inside your head to view your memories. The memories may have been repressed from trauma._

A different voice spoke. It was eerie, for the voice spoke without emotion. Cassiel whirled around, surprised. There was a hooded figure at the door.

"Brother Enoch, welcome. Thank you for taking time to come to the Institute to check on the boy," The golden man whom bore resemblance to the golden girl spoke first. It seemed like everyone in the room had heard the voice in their mind.

Brother Enoch moved towards him. He heard no footsteps. Cassiel shrinked back a little, intimidated. What had he meant by _go inside your head_?

Owen stood by Aurea and Ted, who appeared unnerved by the arrival of the silent brother.

_Fear me not, boy. Are you ready?_

"What are you going to do in my head?" Cassiel tried to keep his voice from trembling. The figure before him was like a ghost.

_I am not a ghost. I am a Silent Brother. I will do nothing but look into your memories. Do not fear. It will be quick. Are you ready?_

Cassiel nodded. There was a sharp pain. He saw some images of a dusty baren area and a lot of darkness around and then, nothing. The images suddenly stopped coming.

Brother Enoch took a step back. _There is something dark in the boy. I was able to catch a glimpse of a dusty baren area. There is a powerful force that is guarding his memories. I cannot tell more. _

The adults in the room glanced at Magnus and Clary. Magnus shrugged, "It wasn't me."

Simon and Isabelle returned their gaze to the silent brother, waiting for him to continue.

_Someone more powerful than Magnus Bane. It is not the work of a warlock._

Cassiel had no idea what was going on. He stared blankly ahead. Aurea frowned while Jace looked pale. The room grew awfully silent.

Finally, Alec spoke, "That sounds strangely familiar. It couldn't be..."


End file.
